Hello there, Welcome to HealthcareMagic.as far as pregnancy is concerned ultrasound is more confirmatory than symptoms.if ultrasound says there is no pregnancy,that means you should look for other reason for these symptoms.you should visit doctor in person to avoid unnecessary stress.

Hi welcome to Healthcaremagic Forum....
I wanted you to know that there are Subjective and Objective signs of Pregnancy.

subjective signs-The classic presentation of pregnancy is a woman with menses of regular frequency who presents with amenorrhea( absent periods), nausea, vomiting, generalized malaise, and breast tenderness.
These symptoms of pregnancy are confirmed by Urine pregnancy test and early trimester obstetric scan.
During 2nd trimester(13-28 wks of pregnancy) there will be fetal movements,the perception of the same is called as Quickening. In an non pregnant women the same perception is due to strong bowel movements in the absence of fetus, this kind of perception falls to a category of PSEUDOCYESIS.
Obstetric scan is Objective signs which will confirm the pregnancy.
In early pregnancy the gestational sac might be missed due to excess of peritoneal fat. Please consult the Obstetrician.